Monofunctional phenol-based compounds such as e.g. phenol, 4-alkyl phenols and 4-cumyl phenol are frequently used as chain terminators in the production of polycarbonates (Kunststoff-Handbuch 3; L. Bottenbruch, Hanser, Munich 1992, p. 127; EP-A 0 353 594).
Polycarbonates having terminal groups derived from cycloalkyl-substituted phenols are already described in general form in U.S. Pat. No. 4,699,971 and U.S. Pat. No. 4,788,276. However, in U.S. Pat. No. 4,699,971 and U.S. Pat. No. 4,788,276 only p-substituted cycloalkyl phenols are explicitly disclosed and cited as being particularly preferred.
Ester-functionalised terminal groups in polycarbonate are likewise already described in general form in CA 13 31 669. However, only p- or p,m-carboxylic acid ester-substituted phenols are described there explicitly and by preference. JP-A 63 21 57 14 describes polycarbonates having reactive terminal groups such as OH and COOH groups.
Chain terminators having the following structures are described in EP-A 09 76 772 specifically for the melt interesterification process: wherein    R1 stands for chlorine, methoxy or ethoxy carbonyl and    R2 stands for an alkyl or alkoxy radical or for an optionally substituted aryl or aryloxy radical.
Also described in EP-A 09 80 861 for the melt interesterification process are salicylic acid derivatives having the following structure: wherein    R1 stands for a methyl or ethyl group and    R2 stands for an alkyl, alkoxy, aryl or aryloxy radical, which is optionally also substituted.
Linear alkyl-substituted and branched alkyl-substituted terminal groups are also known and described e.g. in U.S. Pat. No. 4,269,964. Polycarbonates having alkylamino terminal groups are described in U.S. Pat. No. 3,085,992. Polycarbonates having benzotriazole-substituted terminal groups are known from JP 20 00 06 35 08 A2.
From U.S. Pat. Nos. 3,166,606 and 3,173,891 p-phenyl phenol, for example, is known as a chain terminator for polycarbonates. From U.S. Pat. No. 4,330,663 polyester carbonates are known in which 4-butyl benzoic acid chloride is used as a chain terminator.
WO-A 00/50 488 describes the use of di-tert.-alkyl phenol as a chain terminator.
Polycarbonates that are modified with phenyl propyl phenol, alkyl phenol or naphthol radicals as terminal groups are known from the Japanese laid-open application 57 13 31 49.
Trityl phenol, cumyl phenol, phenoxy phenol and pentadecyl phenol are described in WO-A 01/05 866 as chain terminators for polycarbonate.
From EP-A 10 48 684 and WO-A 99/36 458 polycarbonates are known that are modified with 4-(1,1,3,3-tetramethylbutyl) phenol and other branched alkyl phenols, for example.
According to DE-A 38 03 939 chain terminators having the formula are used, wherein    R1, R2, R3 are the same or different and are C2-C12 alkyl or C8-C20 aralkyl, at least one of the radicals R1 or R2 being a C8-C20 aralkyl radical, and wherein “n” has a value between 0.5 and 1.
Phenols having cycloaliphatic radicals are not described. 2,4- or 2,4,6-substituted phenols are said to be advantageous. Technical mixtures of phenols rather than pure substances are used. The effects of pure substances on the properties of polycarbonate are not described.
EP-A 07 94 209 describes polycarbonates having isooctyl phenol and cumyl phenol terminal groups. JP-A 06 256 499 describes hydroxyaryl-terminated polycarbonates.
Polycarbonates, polyester carbonates and polyesters having the known terminal groups commonly display the disadvantage of a relatively high zero shear-rate viscosity, however, and/or tend towards molecular weight degradation or material discoloration under thermal loading.
Starting from the prior art the object was therefore to provide polycarbonates, polyester carbonates and polyesters having terminal groups, or suitable phenolic compounds to produce said terminal groups, which avoid the disadvantage of a high zero shear-rate viscosity and hence have better processing characteristics. It is also desirable that these terminal groups do not lead to degradation under thermal loading, such as in the extrusion process or injection moulding for example, or in the manufacturing process by the melt interesterification method for example, and thus can also be used e.g. in the melt interesterification method.